Fore limb of human and flippers of whale are embryologically homologous structures. What does the study of homologous structures tell us about evolution?

A. This is the example of adaptive radiation, occurred due to similar group of organisms inhabiting different environments.

B. This is the example of divergent evolution, occurred due to similar group of organisms inhabiting different environments.

C. Similar group of organism with mutations and variations getting naturally selected in different environments.

D. This is the example of convergent evolution, occurred due to similar group of organisms inhabiting different environments.

Which of the following is the correct combination?

• A, B and C

• A and D

• B and D

• Only D

52.

Foster pups were presented to a primiparous rat at the mid gestation period. Which of the following behaviour will be found in the pregnant rat?

• The rat shows maternal behaviour after a few days of presentation of pups.

• The rat attacks and kills the pups every time they are presented.

• The rat rejects the pups after repeated presentation.

• The rat shows fear response for a few days.

The long feather train of a peacock is quoted as an example supporting

• Hamilton's rule

• Zahavi's handicap principle

• The Red Queen hypothesis

• Haldane's rule

In rats, after the delivery of the offspring, mother shows the following behaviors. Which one of the following behaviors is NOT maternal?

• Licking the pups

• Huddling above the pups to access the ventrum

• Lordosis of mother rat

• Bringing back to the nest pups that wander away from it

The following situations might lead to the evolution of monogyny in birds:

A. Male has to assist the female in rearing the offspring.

B. Male guards the female against other males trying to mate with her.

C. One male may not produce enough sperm required to fertilize all the eggs produced by the female.

Which of the above is/ are correct?

• Only A

• Only B

• A and B

• A and C

A few events in the history of life on Earth are given below:

A. Radiation in mammals and birds; Diversification of insects and angiosperms.

B. Primitive plants and fungi colonize land; Diversification of echnoderms.

C. Seed plants appear; Fishes and Trilobites abundant; earliest amphibians and insects.

D. Earliest birds and Angiosperms appeal; Gymnosperms dominant.

E. Invasion of land by primitive land plants and Arthropods.

F. Mass marine extinction; Reptiles radiate; Amphibians decline.

Which of the following is a correct match of the above events with the geological period during which they had occurred?

• A - Ordovician; B - Tertiary; C - Permian; D - Silurian; E - Devonian; F - Jurassic

• A - Permian; B - Devonian; C - Silurian; D - Ordovician; E - Tertiary; F - Jurassic

• A - Tertiary; B - Ordovician; C - Devonian; D - Jurassic; E - Silurian; F - Permian

• A - Permian; B - Devonian; C - Jurassic; D - Tertiary; E - Silurian; F - Ordovician

Three Indian animals- cormorant, lion-tailed macaque and gerbil are to be matched with the ecosystem they inhabit-Wetland (A), Deser (B), Deciduous forest (C), or Rain forest (D). Which of the following is the correct match of each animal with its habitat?

• Cormorant - D; Lion-tailed macaque - C; Gerbil - B

• Cormorant - A; Lion-tailed macaque - C; Gerbil - D

• Cormorant - A; Lion-tailed macaque - D; Gerbil - B

• Cormorant - B; Lion-tailed macaque - C; Gerbil - D

Given below are some of the methods used to assess evolutionary phylogenetic relationships among plant taxa.

A. 16S rRNA sequence

B. Mitochondrial microsatellite

C. Biochemical characterization

D. Morphology

Which two of the above methods can best reveal the evolutionary phylogenetic relationships?

• A and B

• B and C

• C and D

• A and D

Nichrome coated stainless steel electrodes were implanted in a rat brain for chronically recording the electrical activity of deep brain structures. During a study of 3 months, the intensity of electrical signals gradually decreased. The following statements may explain the cause of this observation.

A. The deposition of metallic iron from the electrode tips caused degeneration of some neurons.

B. The gradual accumulation of microglia at the electrode tips increased the resistance of electrodes.

C. The neurons at the electrode tips were hyperpolarized gradually.

D. The threshold for firing action potential in the neurons at the electrode tips was increased sue to prolonged presence of electrodes.

Which one of the following is correct?

• A only

• A and B

• C only

• C and D

Which of the following statements is NOT correct regarding effect of genetic drift?

• It alters allele frequency substantially only in small populations.

• It can cause allele frequencies to change at random.

• It can lead to a loss of genetic variation within populations.

• It can cause harmful alleles to become eliminated.